A new computer interface allows people who suffer from neurodegenerative diseases to create music simply by thinking music. "Evidence suggests that musical participation can be beneficial for people with diseases such as dementia and Parkinson's disease. But people who have almost no muscle movement have generally been excluded from such benefits, and can enjoy music only through passive listening. The development of brain–computer interfaces (BCIs) that enable users to control computer functions by mind alone offer new possibilities for such people. In general, these interfaces rely on the user's ability to learn how to self-induce particular mental states that can be detected by brain-scanning technologies."